The Manhattan Project National Park (MAPR) consists of sites in three locations—Hanford, Washington; Los Alamos, New Mexico; and Oak Ridge, Tennessee—that served as the primary centers of operations during the Manhattan Project, the United States’ top-secret effort to develop atomic weapons to help end World War II.
“The Manhattan Project changed the geopolitical landscape of the world,” says Jonathan Creel, Los Alamos National Laboratory MAPR program manager. “What happened then affects us to this very day, and that is important to share with people.”
But to share these historic stories, the buildings where the work took place must be preserved. A small team of professionals from the Lab together with colleagues from the National Park Service, the National Nuclear Security Administration Los Alamos field office, and the Department of Energy Office of Legacy Management, is focused on sites across Los Alamos National Laboratory, where much of the building and small-scale testing of the first atomic weapons took place.
Dating to the early 1940s, the Los Alamos Manhattan Project facilities were built hastily, many constructed simply of drywall, and expected to last no more than one or two years. “This was a mission that had to be done very quickly, and that’s reflected in the architecture and the infrastructure,” says Laboratory Historian of Science Elliot Schultz.
Now, preservationists are hard at work restoring the facilities. Their location within a secure part of the Laboratory presents an added set of security and logistical concerns. “The unique part of Los Alamos being part of a National Historic Park is this is an active laboratory,” Creel says. “In some places, work is being done right next door.”
Here's a look at three of the preservation projects going on now:
V-Site
The first building constructed at V-Site in 1944 was a small triangular-shaped structure surrounded by an earthen berm. Here, scientists conducted early tests of the first implosion weapon prototypes to ensure that key components could withstand cold temperatures and the vibration of an airplane bomb bay.
A high bay assembly building and covered storage area were added in late 1944 to support the assembly of the Trinity device. Assembly of the device’s high-explosives package took place here in early July 1945.
At one time, V-Site consisted of six buildings, but four of the buildings were destroyed during the May 2000 Cerro Grande Fire. One of the most significant preservation efforts at V-Site included replacing the deteriorating roofs of the two remaining buildings in 2023. Preservationists say the modern sheet roof material will prevent leaks and possible damage to the building and exhibits inside.
Slotin Building
After World War II, work continued at Los Alamos under the operational control of the Manhattan Project, and scientists continued to explore fundamental weapons and plutonium research. On May 21, 1946, scientist Louis Slotin was conducting an experiment involving a subcritical mass of plutonium and beryllium when his hand slipped, leading to a critical reaction and a sudden burst of radiation. Slotin died nine days later from exposure.
Over the years, as the building was remodeled and interior walls were added, the location of the Slotin accident ended up in the center of a hallway. Current preservation efforts at this site are focused on restoring the interior of the building to its original condition by removing walls and components that were added when the building was converted to a workshop after the accident. These additions have made giving tours of the facility difficult. When the building interior is back in its historic configuration, the goal is to replicate what the facility looked like when the accident took place.
Guard shacks
During the Manhattan Project, Los Alamos was a restricted top-secret community, and all personnel had to enter through guard stations, known locally as guard shacks. Two of these shacks recently traveled to Vancouver, Washington, where they are being restored at the National Center for Preservation Technology and Training, a historic preservation research and education center that will help document the preservation process.
“The guard shacks will not only return to the Laboratory in excellent condition, but they will return with excellent documentation of the architectural features of the buildings as well as the entire preservation process, which will help to inform future preservation work on the buildings,” says MAPR cultural resources specialist Jeremy Brunette.
“I’m thrilled to see these buildings are finally getting the care and attention that are due to them,” Schultz says. “It’s exciting as a historian to see that people are really appreciating what these facilities did and how they contribute to the broader story of not only the Manhattan Project, but where we’ve gone as a nation since 1945.” ★
More ways to explore
These six sites offer additional perspectives on New Mexico’s nuclear history.
The Bradbury Science Museum
Los Alamos, New Mexico
As Los Alamos National Laboratory’s public museum, the Bradbury’s goal is to help people understand and appreciate the history and work of the Lab from its Manhattan Project origin to its modern day mission. First established in 1954, opened to the public in 1963, and renamed after Norris Bradbury (the Laboratory’s second director) in 1970, the Bradbury moved to its current location in 1993. Today, the museum continues to highlight diverse aspects of the Lab’s work.
The Los Alamos History Museum
Los Alamos, New Mexico
Featuring information about the Los Alamos homestead era, the Los Alamos Ranch School, the Manhattan Project, and the Cold War, the Los Alamos History Museum includes historic buildings (including a Cold War section housed in the former home of Nobel Laureate Hans Bethe), exhibits, and artifacts from the city’s past. Eventually, the museum will include the J. Robert Oppenheimer home.
The National Museum of Nuclear Science & History
Albuquerque, New Mexico
Established in 1969, the exhibits at this Smithsonian Affiliate museum document nuclear history and science. A 9-acre outdoor area behind the 30,000-square-foot museum building features the largest publicly accessible aircraft collection in the state—in addition to rockets, missiles, cannons, and a submarine sail.
The New Mexico Museum of Space History
Alamogordo, New Mexico
Dedicated in 1976 as the International Space Hall of Fame, the New Mexico Museum of Space History—a Smithsonian Affiliate—emphasizes the significant role that the state of New Mexico has played in the development of the U.S. space program. The museum includes an exhibit showcasing Los Alamos National Laboratory technology developed for the exploration of Mars.
The Trinity site
White Sands Missile Range, New Mexico
The location of the world’s first nuclear detonation is a national historic landmark. Near ground zero, visitors can see Jumbo, a large steel container built (but never used) to contain the explosion, and the McDonald ranch house, where the plutonium core of the bomb was assembled. Public open houses are held twice a year.
The White Sands Missile Range Museum
White Sands Missile Range, New Mexico
The White Sands Missile Range Museum’s mission is “to collect, preserve, and interpret the history of the greater White Sands area—its peoples, lands, and technological contributions in support of the United States Armed Forces—from the prehistoric era to the present.” The museum includes exhibits about the Trinity test, missiles, early rocketry, and the U.S. space program. ★